Electrical signal-translating apparatus



June 1943- E. c. GUEDON 2,320,427

ELECTRICAL SIGNAL-TRANSLATING APPARATUS Filed Sept. 28, 1940 Snnentor [mile 5. Gaza/ 0m (Ittorneg Patented June 1, 1943 V I V 4 V UNITED STATES PATENT OFFICE ELECTRICAL SIGNAL-TRANSLATING APPARATUS Emile 0., Guedon, Audubon, N. J., assignor to Ba- 1110 Corporationof America, a corporation of Delaware Application September 28, 1940, Serial No. 358,757

- Claims. Cl. 179-100.41)

This invention relates to electrical signalularity in the appended claims. The invention translating apparatus, and more particularly to itself, however, both as to its organization and apparatus for reproducing sound from'a phonomethod of operation, as well as additional obgraph record. jects and advantages thereof, will best be under- In the copending application of Harold J. Has- 5 stood from the following description of one embrouck, Jr., Serial No. 326,896, filed March 30, bodiment thereof, when read in connection with 1940, now Patent No. 2,280,763, granted April 21, the accompanying drawing, in which 1942 and assigned to Radio Corporation of Figure 1 is a top plan view of a translating America, there is disclosed a pickup device emdevice embodying my invention and employing ploying a piezoelectric transducer provided with a supporting arm in which the removable transa particular kind of record-engaging needle delating unit is mounted, the top of the supporting signed for long life. Experience has shown that arm being removed to show the arm in section it is preferable to secure the needle to the transfor the sake of clearness, lating device instead of making it readily remov- Figure 2 is a sectional view taken on the line able therefrom since the average user of the II--II of Figure -1 but showing the cartridge in phonograph will not possess the requisite techniside elevation and in operative position on the cal skill for replacing and properly adjusting the supporting arm, needle when it has become worn. To require the Figure 3 is a sectional view taken on a line user of a phonograph equipped with such a pick- IIIIII of Figure 1, and 4 up device to engage the services of a skilled Figure 4 is a view similar to Figure 2 but showtechnician imposes a rather unwarranted limitaing the cartridge partly removed from the suption on him, and the primary object of my presporting arm.

, sent invention is to provide an improved pickup Referring more particularly to the drawing, device of the type under consideration which will wherein similar reference characters designate be free from this handicap. corresponding parts throughouflthere is shown More particularly, it is an object of my present an electromechanical transducer comprising a invention to provide an improved signal transcasing l which encloses a pair of piezo-electric lating device of the type set forth wherein the crystals 3 and with which are associated a pair entire unit can be replaced, when necessary, even of terminal foils or conductors 5 in well-known by one not skilled in the art. manner, the conductors5 terminating on a non- A further object of my present invention is to conductive terminal board I carried by the casing provide an improved signal-translating device I. The crystals 3 are preferably spaced from the as aforesaid which is simple in construction and easing l by suitable blocks 9 of damping material inexpensive in cost. and are clamped at their forward end in well- In accordance with my invention, Iprovide, as known manner by a torsion yoke II which is a unit, a sound transducer which may consist of connected to a suitable needle l3 by means of a a more or less conventional piezoelectric carrigid rod IS in the manner more particularly distridge, as it is usually known in the art, or any closed in the aforementioned patent granted to other suitable electromechanical signal-trans- Harold J. Hasbrouck, Jr.

lating device to which the needle may be either The transducer unit thus far described is slidpermanently connected or connected in such a ably and removably carried by a suitable supportway that it h uld b r m v d from th cap ing arm I! the forward end of which is provided tridge or unit and replaced therein only by .a with a housing l'la in which the unit is received skilled technician for proper adjustment and and concealed in operative position, as clearly operation of the device. The transducer unit is 4:, shown in Figs. 2 and 3. The housin "a includes preferably slidably and removably mounted on a a p ir of ppositely disposed, lon i inally exsuitable supporting arm in such a way that suittending side p e which ca ry a transversely able contacts are made between the unit and a extending, nonconductive terminal block 2| to pair of terminal members on the supporting arm which are fixed a pair of spaced terminal strips for external connection. Preferably, the car- 51) 23 through which external connection may be tridge or the like is provided with a pair of-spring made to a suitable amplifier. 0n the terminal contact members for pressingly engaging the board I are mounted two contact springs 25 aforementioned terminals when the unit is in which are electrically connected to the foils 5 and operative position on the supporting arm, the which are spaced apart the same distance as pressure between the spring-contact members he terminal strips 23, the resilient contact memand the terminal members on the supporting arm hers 25 being arranged to engage the rigid terbeing sufficient to releasably retain the unit in minal strips 23 when the unit or cartridge is in operative position on the supporting arm. operative position within the housing Ila. Thus,

The novel features that I consider characterelectrical connection is provided between the istic of my invention are set forth with particcrystals 3 and the terminal strips 23.

The cartridge is guided in its sliding movement within the housing Ila by a pair of plates 21 which are secured to the side pieces I! and on which the side edges of the terminal board I rest, the inward movement of the cartridge with respect to the housing "a being limited by a pair of projections 29 which extend rearwardly from a front plate 30 on the transducer unit and which are adapted to engage with stops 3i on the side pieces I 9. The pressure of the spring contact members against the terminal strips 23 not only effects a frictional force between these members, but also forces the side edges of the terminal board I against the plates 21, and the friction thus created is effective to releasably retain the transducer unit in the housing "a against too easy or accidental removal. However, the pressure between the contact members 25 and the terminal strips 23 is not so great as to inhibit ready removal of the cartridge from I the casing I la.

The front of the housing Ha has a downwardly extending portion "D with which the front plate is flush when the cartridge is in the fully inserted,- operative position, as shown in Figure 2. As the'cartridge is withdrawn from the housing Ila, the spring contact members 25 spring upwardly as soon as they clear the terminal strips 23 and their free ends assume a position such that they would strike the housing portion llb. This, of course, would obstructcomplete withdrawal of the cartridge from the pickup arm housing, and to avoid this, the housing is provided with a pair of tracks 33 which are engaged by the free ends of the contact members 25 during withdrawal of the cartridge and which depress the latter to enable them to clear the front housing portion IIb.

It will be obvious, from the foregoing description, that I have provided a novel and simple signal translating unit which can be removed easily from its supporting arm. Thus, when the record engaging tip 35 of the'needle becomes worn after several thousand playings, all that the user of the phonograph need do is merely to withdraw the cartridge as a unit from the housing I la and slide back into the housing lla a new cartridge which he can obtain from a dealer. Since the dealer is in a position to supply the customer with cartridges which have been assembled, accurately adjusted and tested by skilled technicians, it is obvious that the customer will always be assured of a unit which is properly suited to the needs of his phonograph.

Although I have shown and described but one embodiment of my invention, it will be obvious to those skilled in the art that many other modifications, as well as changes in that described herein, are possible. For example, instead of providing the terminal strips 23 on the block 2! and the spring contact members 25 on the terminal board 1, these parts may be reversed and the resilient contact members mounted on the block 2| with the strips 23 on the board I. It will also be apparent to those skilled in the art that the signal -translating unit need not necessarily be of the crystal type but may be an electromagnetic unit, an electrodynamic unit, or a unit of any other suitable type. I therefore desire that my invention shall not be limited except insofar as is made necessary by the prior art and'by the spirit of the appended claims.

I claim as my invention:

1. In electrical signal-translating apparatus, the combination of a supporting arm constituting a first part, an electromechanical transducer unit slidably and removably carried by said arm and constituting a second part, means for guiding the relative sliding movement of said apparatus, and friction means separate from said guiding means cooperatively carried by said parts for releasably retaining said unit in operative position on said arm.

2. In electrical signal-translating apparatus, the combination of asupporting arm, a pair of spaced terminal members on said arm, an electromechanical transducer unit slidably and removably carried by said arm, guide means on said arm for guiding the sliding movement of said unit thereon, and a pair of correspondingly spaced, resilient terminal elements on said unit adapted to pressingly engage said terminal members when said unit is mounted in operative position on said arm, the pressure between said terminal elements and said terminal members serving to releasably retain said unit on said arm in said position.

x 3. The invention set forth in claim 2 characterized in that said terminal elements and said terminal members are so arranged relative to said guide means that the pressure between said elements and said members is efiective to pressingly engage said unit against said guide means, the resulting friction between said unit and said guide means being effective to releasably retain said unit on said arm in said operative position.

4. In signal translating apparatus, the combination of a supporting arm, an electromechanical transducer unit slidably and removably received by said arm, guide means on said arm for guiding the sliding movement of said unit thereon, and means for pressing said unit against said guide means, the resulting friction between said unit and said guide means being eifective to releasably retain said unit on said arm against accidental removal therefrom.

5. In phonographic sound reproducing apparatus, the combination of a supporting arm in eluding a housing, a non-conductive terminal block in said housing, a pair of conductive terminal members mounted on said block in spaced relation to each other, and an electromechanical transducer unit comprising a casing, a piezoelectric element in said casing, a record engaging needle cooperatively associated with said element, a nonconductive terminal board carried by said casing, a pair of conductors connected to said piezoelectric element and terminating on said terminal board, and a pair of conductive, resilient strips on said terminal board connected to said conductors and spaced from each other in correspondence with said terminal members, said unit being slidably carried by said housing for movement into and out of operative position thereon and being concealed within said housing when in operative position thereon, and said resilient strips being adaptedto makeelectrical contact with and pressingly engage said terminal members when said unit is in said operative position within said housing for releasably retaining said unit in said operative position and for providing external electrical con- 

